If you are a Small Business customer, find additional troubleshooting and learning resources at the Support for Small Business site.

After you start Microsoft Windows Defender, you click the Tools button at the top of the page. You make several changes to settings that appear on the Tools and Settings page. These settings may include Options, Quarantined items, and Allowed items. Another user logs on to the computer by using a different user account and starts Windows Defender. The changes that you made to the Windows Defender settings now appear to this user.

Technical support for x64-based versions of Microsoft Windows

If your hardware came with a Microsoft Windows x64 edition already installed, your hardware manufacturer provides technical support and assistance for the Windows x64 edition. In this case, your hardware manufacturer provides support because a Windows x64 edition was included with your hardware. Your hardware manufacturer might have customized the Windows x64 edition installation by using unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you need technical help with a Windows x64 edition. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware. If you purchased a Windows x64 edition such as a Microsoft Windows Server 2003 x64 edition separately, contact Microsoft for technical support.

For product information about Microsoft Windows XP Professional x64 Edition, visit the following Microsoft Web site: